Flexible self‐driven sensors can respond to tiny vibrations such as sound waves, blood pressure, heartbeat, etc., and have attracted great attention for their promising applications in wearable devices, in which the electrical signals are triggered by mechanical strength and the coupling of triboelectric and electrostatic induction. Herein, flexible self‐driven sensors assembled with a chitosan (CS) film and polydimethylsiloxane (PDMS) film selected as positive and negative triboelectric layers, respectively, are presented. Conductive fabrics function as electrodes, and polyurethane (PU) foams function as flexible substrates which have advantages of simple integrated structures, ease of manufacturing, and relatively low costs. Tests confirm that the sensor has outstanding flexibility, excellent response performance, and remarkable stability. It is used for real‐time monitoring of human movements, and is based on textiles, providing wearing comfort and is operated without any external power sources as the output voltage of about 30 V can support it. Owing to these advantages, it is believed that a new and convenient strategy to fabricate a novel sensor based on available materials used for human activity detecting and healthcare monitoring is achieved.